/*
 * Copyright (c) 2017 Apple Inc. All Rights Reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */

#import <Foundation/Foundation.h>
#import <dispatch/dispatch.h>

NS_ASSUME_NONNULL_BEGIN

/*
 * CKKSCondition is for implementing one-shot condition variables,
 * based on libdispatch semaphores (which might use condition variables underneath).
 */

@interface CKKSCondition : NSObject

- (instancetype)init;

// Fulfilling this condition will also fulfill the chained condition.
// Fulfilling the chained condition will do nothing to this condition.
- (instancetype)initToChain:(CKKSCondition* _Nullable)chain;

/* Fulfills the condition. Can only be called once per CKKSCondition. */
- (void)fulfill;

/* Wait for the the condition to be fulfilled. The returned result behaves exactly like
   libdispatch's dispatch_semaphore_wait. */
- (long)wait:(uint64_t)timeout;

@end

NS_ASSUME_NONNULL_END
